State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
Environ Res. 2020 Jul;186:109580. doi: 10.1016/j.envres.2020.109580. Epub 2020 Apr 28.
A novel integrated process was established in this study to produce butanol from rice straw. In the first pretreatment, an alternative NaOH/Urea preatment operated at -12 C efficiently removed 10.9 g lignin and preserved 91.54% cellulose and hemicellulose in 100 g rice straw. Subsequently, crude cellulase produced from Trichoderma viride was used to convert pretreated rice straw to mono-sugars for fermentation. The yields of glucose, xylose and arabiose obtained from 100 g rice straw were 31 g, 13.4 g and 0.48 g, respectively, resulting in a 69.45% saccharification efficiency of crude enzyme. Finally, to alleviate the carbon catabolite repression (CCR) and enhance butanol production, the coculture system of Clostridium beijerinckii and Saccharomyces cerevisiae was applied. Compared to monoculture of C. beijerinckii F-6, more sugars were consumed, especially the reduction rate of xylose reached to 81.87%, 32.99% higher than that in monoculture system. With more substrate facilitied into metabolism, the butanol concentration reached to 10.62 g/L corresponding to 0.28 g/g substrate, 115.38% higher than that in monoculture system. Overall, this integrated process was a low-energy consumption and efficient method for butanol production from rice straw.
本研究建立了一种从稻草生产丁醇的新型综合工艺。在第一预处理中，在-12°C 下操作的替代 NaOH/Urea 预处理有效地去除了 10.9 g 木质素，并在 100 g 稻草中保留了 91.54%的纤维素和半纤维素。随后，使用绿色木霉产生的粗纤维素酶将预处理后的稻草转化为单糖进行发酵。从 100 g 稻草中获得的葡萄糖、木糖和阿拉伯糖的产量分别为 31 g、13.4 g 和 0.48 g，粗酶的糖化效率达到 69.45%。最后，为了缓解碳分解代谢物阻遏（CCR）并提高丁醇产量，应用了凝结芽孢杆菌和酿酒酵母的共培养系统。与凝结芽孢杆菌 F-6 的单培养相比，消耗了更多的糖，特别是木糖的还原率达到 81.87%，比单培养系统高 32.99%。随着更多的基质促进代谢，丁醇浓度达到 10.62 g/L，相应的基质得率为 0.28 g/g，比单培养系统高 115.38%。总体而言，该综合工艺是一种从稻草生产丁醇的低能耗、高效方法。
